10th July 2026

Other medications

Digoxin 

Digoxin accumulates in the kidneys even at small doses, as it is excreted renally. A reduced dose is therefore required in renal impairment. Plasma digoxin concentration should be closely monitored, and toxicity is increased by electrolyte disturbances. 

Anticonvulsants 

Phenytoin protein binding is reduced, and its volume of distribution is significantly increased in renal failure. The plasma concentration of unbound drug (which is active) is likely to be amplified. A low plasma level may therefore not necessarily be subtherapeutic.) 

Allopurinol 

Allopurinol is mainly excreted in the urine, and in renal impairment, must have a dose reduction to avoid accumulation. Maximum initial dose of 100mg and increase only if the response is inadequate. 

Colchicine

In renal impairment, dose must be halved for patients with GFR < 10 mL / min. 

Hypoglycaemic drugs 

Metformin should be avoided in patients with a creatinine clearance < 30 mL / min, and in patients with a creatinine clearance of 30 – 60 mL /min should be used cautiously at a reduced dose of 1g. Metformin carries a risk of lactic acidosis in renal impairment, as it may accumulate. Metformin should also be suspended in patients undergoing surgery, trauma, severe infection, or procedures which require contrast studies. 

Risk of hypoglycaemia may be increased from sulfonylureas in renal impairment. Insulins also require dose adjustments as they depend on renal clearance for up to half of their elimination. 

Psychoactive drugs 

In renal impairment, lithium requires dose reduction and monitoring of plasma concentrations. Chronic use of benzodiazepines should be avoided.